• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.12
• /
• pp.8363-8369
• /
• 2015

This study is to be investigate properties of workability, compacting and compressive strength replaced by the illite powder in high fluidity concrete. For this purpose, illite powder has replaced the binder of high fluidity concrete of 5%, 10%, 15%, 20%. After concrete mixing, slump flow test, reach time slump flow 500mm, O-lot test were conducted on fresh high fluidity concrete. And compressive strength was determined 28 days for the hardened high fluidity concrete specimens. According to the test results, the workability, filling height of high fluidity concrete were increased in 10% replacement of illite powder. Furthermore, the compressive strength of high fluidity concrete was increased in 10% replacement of illite powder.. It was possible to confirm that optimal mixture ratio of illite powder seems to exist, and it is shown to be 10% according to our experimental results.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.16 no.5
• /
• pp.59-67
• /
• 2012

During the manufacturing of Portland cement, CO2 gas is also necessarily produced through both decarbonation of calcium carbonate and kiln burning. By partially replacing the Portland cement with limestone powder, which is an inert filler in a concrete mixture, CO2 consumption can be reduced in a construction field. This study is to investigate the fundamental durability characteristics of limestone powder added concrete. Experimental variable was the replacement ratio of limestone powder from 0% to 25% with 5% increment. Durability characteristics were investigated by resistance to freeze-thaw, alkali-silica reaction and de-icing chemical in addition to the properties of fresh concrete. From test results, it was observed that the addition of limestone powder did not significantly affect the resistance to freeze-thaw reaction and de-icing chemical. The addition of limestone powder reduced the occurrence potential of alkali-silica reaction by reducing an alkali content in Portland cement.

• The Korean Journal of Food And Nutrition
• /
• v.20 no.1
• /
• pp.40-46
• /
• 2007

A qualitative investigation Dongchunghacho, Jelly combined with sericultural products prepared from assorted increments(0.5, 1, 1.5 and 2%) of P. japonica powder was performed. The qualitative parameters used to assess P. japonica powder increments included, hysicochemical, textural and sensory properties. The moisture and crude protein content of the Dongchunghacho Jelly were significantly greater than the control(p<0.05). Conversely, Dongchunghacho Jelly showed a propensity towards lower crude fat content than the control group. A positive trend was observed for both mineral content and dark color with increased P. japonica powder. In contrast, texture, hardness, gumminess and chewiness of the Dongchunghacho Jelly decreased with increasing levels of P. japonica powder. Color, taste, texture and overall preference of Dongchunghacho Jelly were optimal in the 1 % P. japonica powder mixture.

• Journal of Powder Materials
• /
• v.26 no.4
• /
• pp.282-289
• /
• 2019

Ti has received considerable attention for aerospace, vehicle, and semiconductor industry applications because of its acid-resistant nature, low density, and high mechanical strength. A common precursor used for preparing Ti materials is $TiCl_4$. To prepare high-purity $TiCl_4$, a process based on the removal of $VOCl_3$ has been widely applied. However, $VOCl_3$ removal by distillation and condensation is difficult because of the similar physical properties of $TiCl_4$ and $VOCl_3$. To circumvent this problem, in this study, we have developed a process for $VOCl_3$ removal using Cu powder and mineral oil as purifying agents. The effects of reaction time and temperature, and ratio of purifying agents on the $VOCl_3$ removal efficiency are investigated by chemical and structural measurements. Clear $TiCl_4$ is obtained after the removal of $VOCl_3$. Notably, complete removal of $VOCl_3$ is achieved with 2.0 wt% of mineral oil. Moreover, the refined $TiCl_4$ is used as a precursor for the synthesis of Ti powder. Ti powder is fabricated by a thermal reduction process at $1,100^{\circ}C$ using an $H_2-Ar$ gas mixture. The average size of the Ti powder particles is in the range of $1-3{\mu}m$.

• Journal of Powder Materials
• /
• v.28 no.1
• /
• pp.31-37
• /
• 2021

This study explores reducing the oxygen content of a commercial Ti-48Al-2Cr-2Nb powder to less than 400 ppm by deoxidation in the solid state (DOSS) using Ca vapor, and investigates the effect of Ca vapor on the surface chemical state. As the deoxidation temperature increases, the oxygen concentration of the Ti-48Al-2Cr-2Nb powder decreases, achieving a low value of 745 ppm at 1100℃. When the deoxidation time is increased to 2 h, the oxygen concentration decreases to 320ppm at 1100℃, and the oxygen reduction rate is approximately 78% compared to that of the raw material. The deoxidized Ti-48Al-2Cr-2nb powder maintains a spherical shape, but the surface shape changes slightly owing to the reaction of Ca and Al. The oxidation state of Ti and Al on the surface of the Ti-48Al-2Cr-2Nb powder corresponds to a mixture of TiO2 and Al2O3. As a result, the peaks of metallic Ti and Ti suboxide intensify as TiO2 and Al2O3 in the surface oxide layer are reduced by Ca vapor deposition.

• Korean Journal of Food Science and Technology
• /
• v.28 no.6
• /
• pp.1104-1110
• /
• 1996

To lessen the initial level of microorganism in kimchi, the preparation method of seasoning mixture was modified and electrolyzed acid-water was substitute for washing water and brine water. Changes in the microbial counts of the red pepper powder-garlic mixture prepared with red pepper powder, garlic and 4.8% (w/w) water (tap water and electrolyzed acid-water) of manufactured kimchi showed that coliform count and E. coli count were reduced to 93% and 98%, of the initial level in the tap water added red pepper powder-garlic mixture and 97% and 99% in the electrolzed acid-water added mixture after 6 hours of mix. After 24 hours of mix, no E. coli was recovered in borth mixtures. Microbial levels were revealed as $2.4{\times}10^5\;CFU/g$ for total count, $2.3{\times}10^5\;CFU/g$ for Lactobacillus count. $1.0{\times}10^2{\;}CFU/g$ of coliform count and $10^1\;CFU/g$ of E. coli count in the seasoning mixture prepared by the general method, and $4.2{\times}10^5\;CFU/g$ of total count, $4.0{\times}10^5CFU/g$ of Lactobacillus count, $1.0{\times}10^3\;CFU/g$ of coliorm count and $4.0{\times}10^2\;CFU/g$ of E. coli count in the mixture propared by the modified method. During fermentation at $10^{\circ}C$, the levels of total and Lactobacillus counts in kimchi prepared by the modified method were significantly lower than those of kimchi were recovered in kimchi prepared by the modified method, whereas there were at the level of $10^1\;CFU/g$ in kimchi prepared by the general method. The pH and acidity of kimchi prepared by the modified method were 4.66 and 0.54%, respectively, whereas those in kimchi prepared b the general method were 4.51 and 0.70%, respectively. But after 14 days of fermentation significant differences were not observed in the changes of microbial, pH and acidity for both kimchi.

• Korean Journal of Food Science and Technology
• /
• v.53 no.2
• /
• pp.174-180
• /
• 2021

The optimal recipe for manufacturing composite honey-based herbal pills mainly comprising Rubus coreanus powder (RCP), black mulberry powder (BMP), and vitamin C was investigated. Honey-based herbal pills were prepared by mixing these powders, binding them with honey, and then forming a round shape. The experiment was designed based on the D-optimal mixture design, which included 12 experimental points with one replicate for three independent variables as follows: RCP (10~35%), BMP (10~35%), and vitamin C (5~10%). In addition, the dependent variables (total phenolic and flavonoid content and antioxidant activity) were measured and used to optimize the manufacturing conditions. The results showed that high amounts of RCP were correlated with high total flavonoid content, whereas the addition of high amounts of vitamin C resulted in higher antioxidant activity. In conclusion, an optimized formulation for the honey-based herbal pill was found to contain 35% RCP, 10% BMP, and 10% vitamin C.

• Journal of Powder Materials
• /
• v.13 no.5 s.58
• /
• pp.321-326
• /
• 2006

Electronic packaging involves interconnecting, powering, protecting, and cooling of semiconductor circuits fur the use in a variety of microelectronic applications. For microelectronic circuits, the main type of failure is thermal fatigue, owing to the different thermal expansion coefficients of semiconductor chips and packaging materials. Therefore, the search for matched coefficients of thermal expansion (CTE) of packaging materials in combination with a high thermal conductivity is the main task for developments of heat sink materials electronics, and good mechanical properties are also required. The aim of this work is to develop copper matrix composites reinforced with carbon nanofibers. The advantages of carbon nanofibers, especially the good thermal conductivity, are utlized to obtain a composite material having a thermal conductivity higher than 400 W/mK. The main challenge is to obtain a homogeneous dispersion of carbon nanofibers in copper. In this paper, a technology for obtaining a homogeneous mixture of copper and nanofibers will be presented and the microstructure and properties of consolidated samples will be discussed. In order to improve the bonding strength between copper and nanofibers, different alloying elements were added. The microstructure and the properties will be presented and the influence of interface modification will be discussed.

• Journal of Conservation Science
• /
• v.32 no.2
• /
• pp.109-121
• /
• 2016

Mother-of-pearl turtle shell lacquerware refers to a decoration made of a mother-of-pearl, a turtle shell and metal wires. This lacquerware features bright color tone as it is produced by sprinkling metal powder over its entire surface. This study aimed to find out its material properties and characteristics by using an optical microscopy and conducting a SEM-EDS analysis on the cross section of lacquer coating. As a result, it was found that charcoal powder and soil powder were mixed for undercoating. Then a mixture of cinnabar lacquer and monoclinic arsenic sulfide mineral ($As_2S_3$) was coated on the undercoating and brass powder was sprinkled on top of it. Especially, a little amount of pigment was found on the lacquer layer, which is distinguished from the colors used for conventional lacquer patterns. In addition, it was also found that the cinnabar lacquer and monoclinic arsenic sulfide mineral were mixed together.

• Culinary science and hospitality research
• /
• v.22 no.7
• /
• pp.1-10
• /
• 2016

The purpose of this study was to determine the desirable mixture ratio of Cirsium setidens Nakai powder to rice flour for the preparation of Sulgidduk. The moisture of samples raged from 36.51% to 40.67%. The addition of Cirsium setidens Nakai powder in the Sulgidduk tended to decrease the lightness (L) in Hunter color value, but to increase the redness (a) and yellowness (b). With increasing Cirsium setidens Nakai powder level, the hardness, springness and chewiness of the samples increased and their cohesiveness decreased. In sensory evaluation, the addition of 5% Cirsium setidens Nakai powder showed the best score in taste and overall preference. Over 3 days of storage, Sulgidduk showed a slightly high total bacterial count compared to control. Therefore, these results suggested that the addition of 5% Cirsium setidens Nakai powder could be applied for making Cirsium setidens Nakai powder Sulgidduk.